1. Field of the Invention
The present invention relates to a nozzle surface cleaning apparatus, a maintenance method using same, and a droplet ejection apparatus, and more particularly to a nozzle surface cleaning apparatus which wipes a nozzle surface by pressing a wiping member against the nozzle surface, a maintenance method using same, and a droplet ejection apparatus.
2. Description of the Related Art
In an inkjet head of an inkjet recording apparatus, foreign matter of various types, such as ink residue, paper dust, or the like, adheres to the nozzle surface and the nozzle edges of the inkjet head with use. When foreign matter adheres to the nozzle surface, ink droplets ejected from the nozzles are affected, variation occurs in the ejection direction of the ink droplets, it becomes difficult to deposit the ink droplets at the prescribed positions on the recording medium, and this becomes a cause of decline in the image quality. Hence, in an inkjet recording apparatus, it is important to remove foreign matter periodically by means of a maintenance method, such as wiping, a dummy jet action, or the like.
For example, Japanese Patent Application Publication No. 2005-074671 describes removing foreign matter by placing a rotatable brush in contact with the nozzle surface of the head, and moving the brush reciprocally in an advancing and retracting direction and a parallel direction with respect to the nozzle surface. Japanese Patent Application Publication No. 2003-266717 describes removing foreign matter by placing a cleaning roller in contact with the ink ejection surface, moving the roller relatively to the ink ejection surface, and controlling the movement speed and rotational speed of the cleaning roller. Japanese Patent Application Publication No. 2005-028758 describes spraying cleaning liquid to which an ultrasonic wave is applied, and cleaning the interior of ink nozzles by means of pressure and the ultrasonic wave.
Moreover, Japanese Patent Application Publication No. 11-314374 discloses an inkjet recording apparatus which includes a wiping member (blade) having a structure which is able to turn in a range of 90 degrees on the nozzle surface, and which executes a first wiping operation of wiping the nozzle plate in a first direction and a second wiping operation of wiping in the direction perpendicular to the first direction.
Further, Japanese Patent Application Publication No. 2007-130807 discloses an inkjet recording apparatus which includes a wiping member for wiping ink adhering to the ejection surface and an absorbing member for absorbing the ink adhering to the ejection surface, the inkjet recording apparatus being composed so as to move the absorbing member in a direction substantially perpendicular to the wiping direction of the wiping member.
Furthermore, Japanese Patent Application Publication No. 2009-226610 discloses a recording apparatus which moves a wiper member reciprocally in a direction perpendicular to the main scanning direction, as well as swinging the wiper member about an axis extending in a direction perpendicular to the ink ejection surface in a plane parallel to the ink ejection surface, and thereby seeking to increase the lifespan of the wiper member.
However, in a case where wiping is performed in the perpendicular direction to the nozzle surface while generating vibration, as described in Japanese Patent Application Publication No. 2005-074671, there is a problem in that damage is caused to the nozzle surface and the liquid repellent film formed on the nozzle surface is broken down. Moreover, the method described in Japanese Patent Application Publication No. 2003-266717 performs the wiping in one direction, and although the foreign matter can be removed by wiping in one direction if the foreign matter is easily removable (if the foreign matter is not adhering very strongly to the nozzle surface), only a portion of the foreign matter can be removed completely by wiping in one direction, if the foreign matter is difficult to remove. The method described in Japanese Patent Application Publication No. 2005-028758 is not adequate due to only performing the cleaning with the cleaning liquid to which the ultrasonic wave is applied. Consequently, in these maintenance methods, there is a problem in that the ejection direction cannot be restored.
Apart from the problems described above, problems such as those described below also exist. FIG. 29A shows a schematic view of a state where ink 604 has adhered to a nozzle surface 602 of an inkjet head 600. The ink 604 shown in FIG. 29A becomes solidified to material firmly adhering to the nozzle surface 602 when drying and increasing in viscosity with the passage of time.
FIG. 29B shows a state where the ink 604 adhering to the nozzle surface 602 has solidified. In this state, cleaning liquid is applied to the nozzle surface 602, and FIG. 29C shows a state where the nozzle surface 602 is wiped using a wiping web 606.
The wiping web 606 wipes the nozzle surface 602 while pulling and extending the ink of increased viscosity adhering to the nozzle surface 602. If the wiping by the wiping web 606 is performed in one direction only, then as shown FIG. 29D, adhering material 610 remains inside the nozzle 608 on the leading edge thereof in the direction of travel of the inkjet head 600 (the direction indicated by the arrow in the drawing) (i.e., the edge on the upstream side in terms of the direction of travel of the wiping web 606).
If adhering material is present inside the nozzle 608 or in the vicinity of the nozzle 608 on the nozzle surface 602, then variation occurs in the ejection direction of the droplets ejected from the nozzle 608, as described previously.
Japanese Patent Application Publication No. 11-314374 discloses a wiping member (blade) having a structure which is rotatable in a range of 90° on the nozzle surface, but does not disclose a specific wiping method (conditions).
The absorbing member disclosed in Japanese Patent Application Publication No. 2007-130807 serves to absorb ink which has adhered to the ejection surface, but beneficial effects in removing solid adhering material cannot be expected. Furthermore, the composition disclosed in Japanese Patent Application Publication No. 2007-130807 performs wiping substantially in one direction with respect to the ejection ports, and beneficial effects in removing hard adhering material cannot be expected.
The recording apparatus disclosed in Japanese Patent Application Publication No. 2009-226610 also performs wiping substantially in one direction with respect to the nozzle openings, and has difficulty in removing hard adhering material.